1. Field of the Invention
The present invention relates to an article transport facility comprising an article transporting body movable along a travel path provided near a ceiling and extending to pass by one or more article transfer locations corresponding to one or more article supports, wherein the article support is supported to a fixed frame installed in the ceiling to be movable relative to the fixed frame between a projected position, for article transfer, which projects toward the travel path, and a pulled back position which is farther away from the travel path, and wherein the article transporting body is configured to deliver an article to and receive an article from the article support in the projected position when the article transporting body is at rest in the article transfer location.
2. Description of the Related Art
An article transport facility, such as one described above, has a plurality of article transfer stations, to which articles are to be transferred, and which are arranged on the floor along the travel path. One or more article transporting bodies transport articles between the stations by rising and lowering a grip portion which is adapted to hold an article with the article suspended therefrom.
Article supports are provided to temporarily store articles to be transported to respective stations. An article support is usually located in the pulled back position which is located away from the fixed frame provided, for example, to one or both sides of the travel path so as not to interfere with the movement and such of the article transporting bodies. When storing an article in the article support, or when transporting an article currently stored in the article support, the article support is moved from the pulled back position to the projected position to have the article delivered to the article support by the grip portion, or to have the article received from the article support by the grip portion.
This type of article transport facility is installed, for example, in a clean room and the articles are temporarily stored in the article supports in a clean environment with little dust, by moving clean air from the ceiling region to a lower region. Therefore, a substantial disruption, for example by the fixed frame, of the flow of the clean air from the ceiling region to the lower region may result in degradation of clean air.
To this end, in a conventional article transport facility, an article support has a right-and-left pair of support arms that are supported to the fixed frame so as to be movable in the far-near direction, which is toward and away from the fixed frame, and that extend downwardly from the fixed frame and then toward the travel path in the far-near direction, and connecting members for connecting the portions, of the right-and-left pair of support arms, that extend toward the travel path in the far-near direction. (See, for example, Patent Document 1.) The right-and-left pair of support arms are spaced apart by a distance greater than the width of the article along the direction of the travel path so that the portions extending in the direction toward the travel path in the far-near direction may contact the sides of the article over its full width in the far-near direction. A plurality of connecting members is provided spaced apart from each other in the far-near direction, and are configured such that each of the plurality of connecting members contacts the bottom of the article.
In the conventional article transport facility, one pair of right and left fixed frames is sufficient to support each of the right-and-left pair of support arms for movement in the far-near direction. Therefore, the width of the fixed frame in the direction along the travel path can be made small, which can help prevent a substantial disruption of the flow of clean air from the ceiling region to the lower region by the fixed frame.    Patent Document 1: Japanese Patent Application Publication No. 2007-91463 (Pages 17-21; FIGS. 16-21)